Investigative Conservation involves the scientific investigation of objects from the collections to better understand their manufacture, technology and history.
Techniques which are brought to bear on individual artefacts are varied, and range from microscopic examination, through to a range of sophisticated forensic analyses.
Examinations can be carried out in-house, including analysis by microscopy, X-ray and X-ray fluorescence. Infrared and UV light sources are used for authentication purposes and to detect previous repairs.
X-rays are used routinely for the examination of excavated archaeological metalwork – especially for the examination of iron artefacts. Centuries of corrosion in the ground means that objects, when excavated, can be covered in voluminous concretion. It is often impossible by purely visual means, to make out the original object. At a basic level, X-rays enable conservators to see the shape of the artefact within the layers of corrosion. X-rays can also reveal details of how an object was made and used, and details of decoration that was applied e.g. metal plating, inlay, armatures within sculpture etc. The National Museum of Ireland encourages the x-raying of all excavated metalwork, and makes its facilities available to archaeological conservators working in Ireland.
X-ray fluorescence (XRF) is an analytical technique which can identify inorganic elements, e.g iron gall pigments in the text of a manuscript, the constituent alloys in a metal artefact, or toxic pesticide residues on organic objects. This can be used to aid in the authentication and dating of objects, e.g. the relative proportions of gold and silver act as a chronological indicator in prehistoric gold alloys, e.g. Iron-age gold alloys have high levels of silver present. It can also tell us what metals were used as plating and inlays on a wide range of artefacts.
More sophisticated analysis involving techniques such as multispectral imaging, scanning electron microscopy, MRI (magnetic resonance imaging) and CT (computerised tomography) scanning is arranged with other institutions in Dublin.